/Engine/Source/Editor/DataLayerEditor/Public/DataLayer/DataLayerEditorSubsystem.h
Changes the IsLoadedInEditor flag of the DataLayers to the provided state
bool SetDataLayersIsLoadedInEditor ( const [TArray](API\Runtime\Core\Containers\TArray)< [UDataLayerInstance](API\Runtime\Engine\WorldPartition\DataLayer\UDataLayerInstance) * > & DataLayers, const bool bIsLoadedInEditor, const bool bIsFromUserChange )